Patrick Buckley 7f1b0acf7a Bound search tool output against pathological inputs (#473)
* Bound search tool output against pathological inputs

Replaces the per-line truncation with a fully bounded pipeline so the
search tool can no longer overflow the LLM context — or OOM the parent —
on minified bundles, multi-GB JSONL records, or huge result sets.

Backend:
- Prefer ripgrep when on PATH; grep is the fallback. Detection is
  cached via functools.cache.
- ripgrep flags do most of the bounding natively: --max-columns 1024
  + --max-columns-preview, --max-filesize 10M, --max-count 100,
  --no-config, --no-messages, plus negative globs for the same
  noisy directories grep has been excluding.
- ripgrep added to the Dockerfile.

Streaming subprocess (_search_capture):
- subprocess.Popen with a streaming, byte-capped stdout read (4 MB).
  Defends against single-line files (training data, minified bundles)
  that would have OOM'd the previous subprocess.run capture.
- threading.Timer watchdog enforces tool_timeout even when the
  pipe read is blocked in the kernel — proc.wait(timeout=…) alone
  was insufficient because the read sat ahead of it.
- Stderr drained in a daemon thread to avoid pipe-deadlock when the
  child writes to stderr while we're still reading stdout. Cap on
  captured stderr keeps a hostile child from growing the buffer.

Tier-based formatter (_format_search_results):
- Tier 1: full path:line:content output, stream-emitted with a
  running-cost short-circuit so we never materialize past the budget.
- Tier 2: K samples per file with overflow notes; K is computed
  analytically from budget / file_count / avg-line-length so we hit
  the right ladder rung in a single pass.
- Tier 3: per-file counts only, also budget-bounded with a tail line
  reporting the omitted files. Sorted by descending count.
- Total output budget (32 KB) is well under tool_truncation, so the
  head+tail _truncate_output strategy never silently drops middle
  files in a search result.

Argument injection fix:
- The ripgrep arg list was missing the `--` separator that the grep
  branch already had. With auto_approve on the search tool, that was
  exploitable: path='--pre=COMMAND' would have made ripgrep run the
  script as a per-file preprocessor and surface its stdout. Added
  `--` and a regression test.

State-machine cleanup in _exec_search:
- rc < 0 (signal-killed by something other than us) now surfaces a
  dedicated 'killed by signal N' message instead of being parsed as
  success.
- capped + zero parsed records (e.g. one multi-MB line with no \n)
  now returns a dedicated byte-cap message instead of the malformed-
  output message that previously masked the real cause.
- _report_tool_result descriptions now match the returned payload
  (no more 'no matches' tag on a 'malformed' payload).

Defence-in-depth on env scrub:
- RIPGREP_CONFIG_PATH, GIT_CONFIG, GIT_CONFIG_GLOBAL, GIT_CONFIG_SYSTEM
  added to _EXPLICIT_SCRUB. We pass --no-config on the rg CLI today,
  but if a future caller forgets the flag, an attacker who can set
  one of these env vars could plant a config containing --pre=… and
  recreate the same RCE shape.

Tests:
- TestSearchLineTruncation rewritten to mock _search_capture instead
  of subprocess.run (the previous tests passed ChatSession kwargs
  that no longer satisfy the constructor).
- TestSearchBackendSelection covers rg/grep detection and arg
  construction, including the --pre flag-injection regression.
- TestSearchOutputBudget exercises Tier 1/2/3 directly.
- TestSearchCaptureStreaming spawns real Python subprocess writers
  to exercise the byte-cap trim, mega-line-no-newline edge case, the
  watchdog timeout when the child writes nothing, and the stderr
  drain under load.
- test_env_scrub picks up the new tool-config keys.

* Address Copilot review on #473

- Budget the Tier 2/3 header up front so the formatter's emission stays
  strictly within _SEARCH_OUTPUT_BUDGET. Previously the fit checks only
  counted body bytes, letting the final string overflow by ~120 chars
  (header + separator) and triggering _truncate_output's head+tail
  dropout — exactly the shape this code was trying to avoid.
- Restore the (5, 3, 1) ladder in Tier 2: the analytical K from perf-2
  is kept as a starting estimate, but if that K's actual emission
  doesn't fit (the estimate ignores the header and overweights shared-
  path compression) we step down through the ladder before falling
  through to Tier 3. The previous one-shot K could collapse to counts-
  only when 3/file or 1/file would have fit.
- Only normalise rc to 0 in the capped-output path when rc < 0 (our
  SIGKILL). There's a narrow race where the child can exit naturally
  between our read and our kill; preserving a non-negative rc means
  rg's rc=2 ('matches found but some files had errors') no longer
  silently turns into a clean success when the byte cap also fires.
- Clarify _MAX_SEARCH_LINE_LENGTH doc: the cap applies to the content
  portion (after path:lineno:), not the whole emitted line.
- Add explanatory comments on the two intentional `except Exception:
  pass` blocks in _search_capture (stderr drain, pipe close in the
  cleanup finally) so static analysis and future readers can see the
  silence is deliberate.
- Tighten the budget tests: now assert strict `<= _SEARCH_OUTPUT_BUDGET`
  instead of the +512-char slack that was masking the header overflow.
- New regression tests:
  - Tier 2 ladder step-down (K=5 over budget, K=3 fits, no Tier 3 fall-through)
  - capped + rc=2 surfaces stderr instead of being normalised to success
  - capped + rc<0 (our SIGKILL) flows through as a partial-result success

* chore(search): post-review cleanup

Follow-up to the Copilot-review fixes in 39d2aa2 — these are all small
quality items (no behaviour change, no new tests).

- q-1: collapse the Tier 2 candidates filter to a single expression.
  Drops the redundant inner ``max(estimated_k, 1)`` and the unreachable
  ``if not candidates`` branch (the ladder ends in 1 and ``estimated_k``
  is already floored at 1, so the comprehension always yields ≥ ``[1]``).
  ``or [...]`` is kept as defence against future ladder changes.
- q-2: update _format_search_results docstring to match the new ladder
  semantics (analytical seed → step down through (5, 3, 1) from the
  highest rung ≤ the estimate). The previous wording suggested every
  Tier 2 attempt started at 5.
- q-3: combine the two ``from turnstone.core.session import ...``
  statements in test_tier2_steps_down_ladder_before_falling_to_tier3
  into a single top-of-function import (matches the surrounding tests).
- q-4: shorten the explanatory comments on the two best-effort cleanup
  paths in _search_capture to one line each. Both sites now read with
  the same shape ("# best-effort: pipe may be torn down by ...").
- q-5: trim the _MAX_SEARCH_LINE_LENGTH comment from 7 lines back to 3.
  Keeps the load-bearing semantic (cap is on the content portion only)
  and the pathological-line defence; drops the paths-aren't-bounded
  parenthetical, which was background reading rather than WHY.
2026-05-04 02:59:35 -07:00
2026-05-03 13:44:50 -07:00
2026-05-04 02:59:35 -07:00

Turnstone

CI PyPI Python License

Multi-node AI orchestration platform. Deploy tool-using AI agents across a cluster of servers with direct HTTP routing, interactive interfaces, and enterprise governance.

Turnstone coordinator — parallel tool batches with judge-graded approval and child workstream tracking

Named after the Ruddy Turnstone (Arenaria interpres) — a shorebird that flips stones to discover what's hiding underneath.

Release Tracks

Track Install Docker Description
Stable pip install turnstone ghcr.io/turnstonelabs/turnstone:stable Production-grade. Bugfixes only.
Experimental pip install turnstone --pre ghcr.io/turnstonelabs/turnstone:experimental New features. May have rough edges.

See docs/releasing.md for the full release process.

What it does

Turnstone gives LLMs tools — shell, files, search, web, planning — and orchestrates multi-turn conversations where the model investigates, acts, and reports.

  • Interactive sessions — terminal CLI or browser UI with parallel workstreams
  • Cluster dashboard — real-time view of all nodes and workstreams with console routing proxy
  • Intent validation — LLM judge evaluates every tool call with risk assessments and evidence
  • Governance — RBAC, OIDC SSO, tool policies, skills, usage tracking, audit logs
  • Multi-provider — OpenAI-compatible APIs (vLLM, llama.cpp, NIM), Anthropic Messages API, and Google Gemini
  • MCP support — external tool servers with native deferred loading (Anthropic/OpenAI) or BM25 fallback

Turnstone system architecture

Quickstart

pip install turnstone

# Terminal REPL
turnstone --base-url http://localhost:8000/v1

# Browser UI
turnstone-server --port 8080 --base-url http://localhost:8000/v1

# Cluster dashboard
pip install turnstone[console]
turnstone-console --port 8090

For PostgreSQL (recommended for production):

pip install turnstone[postgres]
export TURNSTONE_DB_BACKEND=postgresql
export TURNSTONE_DB_URL="postgresql+psycopg://user:pass@localhost:5432/turnstone"
turnstone-server --port 8080 --base-url http://localhost:8000/v1

Docker

cp .env.example .env  # edit LLM_BASE_URL, OPENAI_API_KEY, etc.
docker compose --profile production up

See QUICKSTART.md for the bootstrap wizard and docs/docker.md for Docker configuration and profiles.

Programmatic (SDK)

from turnstone.sdk import TurnstoneServer

with TurnstoneServer("http://localhost:8080", token="tok_xxx") as client:
    ws = client.create_workstream(name="demo")
    result = client.send_and_wait("Analyze the error logs", ws.ws_id, auto_approve=True)
    print(result.content)

Tools

Built-in tools for shell, files, search, web, memory, notifications, and autonomous sub-agents — plus external tools via MCP with native deferred loading. See docs/tools.md for the full reference and docs/mcp-registry.md for MCP configuration.

Architecture

Single-node: Client → Server (direct HTTP + SSE). No external dependencies beyond the database.

Multi-node: Client → Console (rendezvous routing proxy) → Server nodes. The console picks the target node for each workstream via rendezvous (HRW) hashing over the live service registry — pure function of (ws_id, live_nodes), no stored bucket state, deterministic across readers. A node join or drop only re-routes the keys that score highest on the affected node.

Component Purpose
turnstone Terminal CLI (REPL)
turnstone-server Web UI + REST API + SSE events
turnstone-console Cluster dashboard + routing proxy + admin panel
turnstone-channel Channel gateway (Discord and Slack adapters)
turnstone-admin User/token management CLI
turnstone-eval Eval harness for prompt/tool optimization
turnstone-bootstrap LLM-guided setup wizard

Diagrams

UML diagrams in docs/diagrams/:

Diagram Description
System Context Components and external dependencies
Package Structure Python modules and dependency graph
Core Engine SessionUI, ChatSession, LLMProvider
Conversation Turn Message lifecycle through the engine
Tool Pipeline Prepare / approve / execute
Workstream States State machine transitions
Console Data Flow Dashboard data collection
Deployment Docker Compose topology
Auth JWT, scopes, login flows
Channels Discord / Slack adapters + routing
Judge Intent validation pipeline
OIDC SSO authorization code flow

Documentation

Topic Link
Configuration reference docs/settings.md
API reference docs/api-reference.md
Docker deployment docs/docker.md
Intent validation (judge) docs/judge.md
Governance & RBAC docs/governance.md
OIDC SSO docs/oidc.md
TLS / mTLS docs/tls.md
Channel integrations docs/channels.md
Console dashboard docs/console.md
Eval harness docs/eval.md
Tools reference docs/tools.md
MCP integration docs/mcp-registry.md

Requirements

  • Python 3.11+
  • An OpenAI-compatible API endpoint, Anthropic API key, or Google Gemini API key
  • Optional: PostgreSQL (pip install turnstone[postgres]), Anthropic (pip install turnstone[anthropic])
  • Git LFS for cloning (diagram PNGs)

License

Business Source License 1.1 — free for all use except hosting as a managed service. Converts to Apache 2.0 on 2030-03-01.

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